[symmo]

How can I tell if the oil is circulating in my C5? The oil window gives no clues as the level does not change when the engine is running. I did remove the push rod cover and start the engine and oil splattered everywhere, but that could have just been pressure or fling off from the rotor.

[Haggis]

Not the easiest to confirm.
You could put a pressure gauge into the hole where the oil temp sensor sits.
Or you can buy a see through window for tappet cover. Fast forward to 11.30 minutes.
https://youtu.be/BtEpZ1-FhDI
Or you could make a temporary perspex one and watch all the oil that goes to the top end drain back down the pushrod tunnel, through a hole between the lifters and then lubes the cams and gears.
You can also drill out the blanking plug from the oil filter housing, tap a thread to take a pressure gauge.
https://youtu.be/G3qeE655qNY

[Richard230]

If the oil is not circulating in the engine, wouldn't the hydraulic adjusting tappets make a horrible clanking noise when the engine is running?

[symmo]

If the oil is not circulating in the engine, wouldn't the hydraulic adjusting tappets make a horrible clanking noise when the engine is running?

Thats a good point never thought of that.

[axman88]

It seemed to me when looking at the oil circulation diagram in the manual, that there existed at least two parallel flow paths, not all the oil that lubricates the bottom end goes to the top, and it could be possible that that the lifters would have sufficient pressure to pump up, while blockage exists elsewhere, like in the channels to the heads, or back down.

I saw an India RE mechanic's video wherein the engine was run with the valve covers removed to verify oil was reaching the valve gear.  I did this, and observed quite a lot of oil was reaching this point.  Made quite a mess!  If I try this again, maybe I'll do it in my buddy's garage, he's the one who keeps trying to convince me that my garage is the best place for spraying his Porsche's undercarriage with used motor oil.

Last, I recall seeing video and discussion of a point on the UCE side cover adjacent to the oil filter housing, which can be drilled and tapped ( 1/8 NPT?) so a mechanical oil pressure gauge, or sending unit, or pressure tap, can be installed at this point.  As I recall, I think there is already an indentation cast into the cover at this point?

[symmo]

I've sent for a clear tappet window as in Haggis's post, and the idea of installing an oil pressure gauge is something I might consider, as there is a tapping for it in the oil filter housing as the video shows. Thing is whenever I start my old Matchy twin I check for oil circulation without fail, but modern bikes just assume the oil circulates, there's not even an oil pressure light.

[Guaire]

If the oil is not circulating in the engine, wouldn't the hydraulic adjusting tappets make a horrible clanking noise when the engine is running?

Like, YES!